The present invention relates to ultrasonic transducer element, and more particularly relates to an improved construction of a focus-type ultrasonic transducer element including a polymer piezoelectric film operating as a transmitter and/or receiver of ultrasonic waves.
Various types of focus-type ultrasonic transducer elements have been proposed. In one example, the sonic wave emanative surface is formed in a cylindrical or concave pattern. In another example, a plurality of ultrasonic transmitter elements are arranged on a flat surface and drive phases of the elements are chosen so that sonic waves emanated from the elements are focussed upon a fixed point in front of the transducer element with mutual interference.
These conventional transducer elements, however, are in general complicated in construction, difficult in manufacturing and high in cost. In particular, complicated process and arrangement are required for driving the transducer elements for generation of ultrasonic waves.